Kindlin-2 regulates hemostasis by controlling endothelial cell-surface expression of ADP/AMP catabolic enzymes via a clathrin-dependent mechanism
Kindlin-2 regulates hemostasis by controlling endothelial cell-surface expression of ADP/AMP catabolic enzymes via a clathrin-dependent mechanism
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DOI：
10.1182/blood-2013-04-497669
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发表时间：
2013-10-03
期刊：
影响因子：
20.3
通讯作者：
Plow, Edward F.
中科院分区：
文献类型：
--
作者：
Pluskota, Elzbieta;Ma, Yi;Plow, Edward F.
Kindlin-2是一种广泛分布的细胞骨架蛋白，与整合素活化有关，其缺失在小鼠中具有胚胎致死性。在本研究中，我们测试了kindlin-2（+/-）小鼠的止血是否会受到干扰。kindlin-2（+/-）小鼠出血时间和颈动脉闭塞时间显著延长。野生型小鼠和kindlin-2（+/-）小鼠血浆中关键凝血/纤溶蛋白的浓度/活性以及血小板计数和聚集相似，而kindlin-2（+/-）内皮细胞（EC）对5 '-二磷酸腺苷（ADP）或低浓度其他激动剂诱导的血小板聚集的抑制作用增强。在Kindlin-2（+/-）EC上，参与ADP/腺苷5 '-单磷酸（AMP）降解的两种酶，三磷酸腺苷（ATP）二磷酸水解酶（CD 39）和外-5'-核苷酸酶（CD 73）的细胞表面表达增加2 - 3倍，导致ATP/ADP催化活性增强和腺苷（血小板聚集抑制剂）的产生。在kindlin-2（+/-）小鼠中，EC表面的CD 39和CD 73运输发生改变。在机制上，这归因于kindlin-2与网格蛋白重链的直接相互作用，从而控制CD 39和CD 73的内吞作用和再循环。Kindlin-2与网格蛋白的相互作用不依赖于其整合素结合位点，但仍依赖于其F3亚结构域内的一个位点。因此，kindlin-2调节控制血小板反应和止血的EC表面酶的运输。
Kindlin-2, a widely distributed cytoskeletal protein, has been implicated in integrin activation, and its absence is embryonically lethal in mice. In the present study, we tested whether hemostasis might be perturbed in kindlin-2(+/-) mice. Bleeding time and carotid artery occlusion time were significantly prolonged in kindlin-2(+/-) mice. Whereas plasma concentrations/activities of key coagulation/fibrinolytic proteins and platelet counts and aggregation were similar in wild-type and kindlin-2(+/-) mice, kindlin-2(+/-) endothelial cells (ECs) showed enhanced inhibition of platelet aggregation induced by adenosine 5 '-diphosphate (ADP) or low concentrations of other agonists. Cell-surface expression of 2 enzymes involved in ADP/adenosine 5 '-monophosphate (AMP) degradation, adenosine triphosphate (ATP) diphosphohydrolase (CD39) and ecto-5 '-nucleotidase (CD73) were increased twofold to threefold on kindlin-2(+/-) ECs, leading to enhanced ATP/ADP catabolism and production of adenosine, an inhibitor of platelet aggregation. Trafficking of CD39 and CD73 at the EC surface was altered in kindlin-2(+/-) mice. Mechanistically, this was attributed to direct interaction of kindlin-2 with clathrin heavy chain, thereby controlling endocytosis and recycling of CD39 and CD73. The interaction of kindlin-2 with clathrin was independent of its integrin binding site but still dependent on a site within its F3 subdomain. Thus, kindlin-2 regulates trafficking of EC surface enzymes that control platelet responses and hemostasis.